Week 16 - System Integration
Individual Assignment:
- Design and document the system integration for your final project
This week is about system integration and I will go throigh various aspects of this topic by discussing my final project both at the current prototyping stage and in regards to future improvements.
System Diagram
Here is a system diagram visualizing the main functions of the sun tracker.
I also made a rough assembly tree.
Design
As with all new developments the resources are limited (time, money, material) and I have to deal with a lot of restrictions and limitations. My approach is to try to account for these limitations and also for possible, unexpected delays or failures.
I was very aware of the production processes I could possibly use and the equipment I had access to. My decision to 3D-print as much components as possible can be explained by the following points.
- confident and experienced in 3D modeling and 3d printing
- fast prototyping and spiral development
- huge freedom of design and complex shapes possible
- lightweight but strong components that are weather resistant
During the 3D design process I made sure to create 3D-print friendly parts with round corners, fillets and little need for support. Also the size of the parts was limited by the build volume of the largest printer I had access to - which determined the split plane for the large housing.
This is the first time I used heat inserts and I find it very convenient, even though the price is quite high, compared to standard hex nuts, which can usually be used in a similar way.
Because the part has to be assembled and disassembled, I used mostly standard DIN EN ISO bolts and nuts of various types. Not all sizes and types are available in our local shop, so I had to consider that in my design.
The complete assembly was drawn in Fusion, which gives a good overview about all components, possible interference and I can extract the BOM list and use it for shopping and assembly.
Because I made all the design from scratch, I never had any issues to know how to assemble the machine or to identify the parts. However, it might be clever and easy to establish a part number system with revision number for the next iteration. I could 3D print the part number directly to the parts.
Bill of Materials
I split the BOM up into three tables for better oversight.
Purchased parts, mechanical
| Pos | Qty | Description | Supplier | Price | Sum |
|---|---|---|---|---|---|
| 1 | 2 | GT2 Timing belt 356mm | MaiLeXun | $1,51 | $3,02 |
| 2 | 2 | GT2 Timing belt pulley 16T | MaiLeXun | $1,11 | $2,22 |
| 3 | 2 | NEMA17HS4401 Stepper Motor | Hanpose | $8,35 | $16,70 |
| 4 | 4 | Ball Bearing 62200-2RS | BCE Bearing | $3,05 | $12,20 |
| 5 | 2 | Ball Bearing 61900-ZZ | BCE Bearing | $0,76 | $1,52 |
| 6 | 4 | Ball Bearing 61821-2RS | BCE Bearing | $12,41 | $49,64 |
| 7 | 2 | Magnet Diametric Ø6 x 3 | DigiKey | $0,72 | $1,44 |
| 8 | 1 | M12 Connector | DigiKey | $10,52 | $10,52 |
| 9 | 1 | Base plate 3mm AISI304 | Local Shop | $30 | $30 |
| 10 | 8 | M6 Insert Stainless Steel | Mouser | $0,92 | $7,36 |
| 11 | 5 | M5 Insert Stainless Steel | Mouser | $0,69 | $3,45 |
| 12 | 1 | Air Vent IP67 M32x1,5 | Mouser | $27,65 | $27,65 |
| 13 | 1 | Carbon Fibre Tube Ø12mm | Easycomposites | $16,22 | $16,22 |
| 14 | 1 | Carbon Fibre Hexagon Tube 14mm | Easycomposites | $23,07 | $23,07 |
| 15 | 2 | Hex Bolt M10x80 A4-70 | Ísól | 131kr | 262kr |
| 16 | 6 | Hex Nut Nylon M10 A4 | Ísól | 33kr | 198kr |
| 17 | 4 | Socket Head Bolt M10x55 A4-70 | Ísól | 122kr | 488kr |
| 18 | 6 | Button Head Bolt M6x12 | Ísól | 16kr | 96kr |
| 19 | 5 | Button Head Bolt M5x12 | Ísól | 11kr | 55kr |
| 20 | 10 | Hex Nut Nylon M6 A4 | Ísól | 9kr | 90kr. |
| 21 | 2 | Hex Nut Nylon M5 A4 | Ísól | 5kr | 10kr |
| 22 | 4 | Hex Nut Nylon M8 A4 | Ísól | 15kr | 60kr |
| 23 | 1 | Hex Nut M6 A4 | Ísól | 6kr | 6kr |
| 24 | 8 | Socket Head Bolt M6x30 A4-70 | Ísól | 22kr | 176kr |
| 25 | 4 | Hex Head Bolt M8x60 A4-70 | Ísól | 67kr | 268kr |
| 26 | 4 | Hex Head Bolt M6x40 A4-70 | Ísól | 31kr | 124kr |
| 27 | 2 | Socket Head Bolt M6x40 A4-70 | Ísól | 35kr | 70kr |
| 28 | 4 | Oversized Washer M6 A4 | Ísól | 9kr | 36kr |